1. Field of the Invention
The present invention relates to an image forming apparatus for forming an image on a recording material.
2. Description of the Related Art
There is an image forming apparatus including a pressure releasing mechanism for automatically releasing pressure applied to a fixing nip portion to improve jam processability in a fixing unit of the image forming apparatus or to prevent deformation of a component. If the fixing unit is removable from a main body of the image forming apparatus, the pressure releasing mechanism is provided in the fixing unit, and a power source for driving the pressure releasing mechanism is provided in the main body of the image forming apparatus.
After the fixing unit is removed from the main body of the image forming apparatus, a pressure release cam in the pressure releasing mechanism in the fixing unit may move due to application of a shock to the fixing unit, for example. Consequently, a phase of the pressure release cam and a phase of a coupling provided in the main body of the image forming apparatus for transmitting power to the pressure release cam do not match each other. Therefore, the fixing unit cannot be mounted on the main body of the image forming apparatus.
As a countermeasure, Japanese Patent No. 5511598 discusses a configuration in which even if a phase of a pressure release cam and a phase of a coupling in a main body of an image forming apparatus do not match each other, the phase of the pressure release cam is made to match the phase of the coupling in synchronization with an operation for mounting a fixing unit on the image forming apparatus.
However, in this configuration, the fixing unit requires a shape for moving the pressure release cam in contact with the coupling in the main body of the image forming apparatus. To move the pressure release cam by an operation for mounting the fixing unit on the main body of the image forming apparatus, a large force is required when the fixing unit is mounted.